The present invention relates to a vehicular air-conditioner which adjusts temperature environment of a vehicle interior.
In order to improve temperature environment of a vehicle interior, a vehicular air-conditioner sends conditioned air whose temperature adjustment has been performed to the vehicle interior. Japanese Patent Application Laid-open No. 2001-105846A discloses that elevating of a cooling performance of a heat exchanger for cooling during vehicle deceleration recovers deceleration energy of a vehicle without giving uncomfortable feeling to a vehicle occupant, thus advantageously saving fuel consumption. According to this, a vehicle occupant great feels more uncomfortable, as a blow-off temperature of conditioned air into the vehicle interior varies greater. On the other hand, the limitation of variation range for a vehicle occupant not to feel uncomfortable is varied according to a blow-off air-flow rate into the vehicle interior. In view of this fact, a target evaporator has a decrement of blow-off temperature during vehicle deceleration. The decrement of the blow-off temperature is set to become smaller, as a target air-flow rate becomes from Low towards High. Thereby, the decrement becomes great when an air blow rate is small, thus advantageously saving fuel consumption without giving uncomfortable feeling to a vehicle occupant.
A compressor in an air-conditioner is operating even during vehicle deceleration. Even when a throttle interlocked to an accelerator pedal is in a full closed state, an idle speed control valve (hereinafter, “ISC valve”) which controls engine revolutions during idling operation is opened or closed. The opening or closing permits an intake air volume to be increased, thus increasing the engine revolutions. This permits an engine to be controlled not to stop due to a load of the compressor.
A passenger vehicle employs a brake apparatus. The brake apparatus utilizes a differential pressure between the atmosphere pressure and a boost pressure of the engine to amplify a pressing force of a driver on a brake pedal until the force reaches a braking force sufficient to stop a vehicle during running thereof.
Accordingly, when the throttle is fully closed in a state that an air-conditioner is operating, an intake air volume into the engine is increased by the ISC valve for operating the compressor. The boost pressure is maintained due to the increase until the throttle is fully closed in a state that the air-conditioner has stopped. That is, a differential pressure between the atmospheric pressure and the boost pressure is reduced, deteriorating engine braking effect. Thus, there is a possibility that the reduction of the differential pressure deteriorates a braking performance in dependence on the structure of the brake apparatus.